Re: [PATCH] Fix `window-at' and `coordinates-in-window-p'

[Lőrentey Károly]

Luc Teirlinck <address@hidden> writes:
> After taking a closer look at your patch, I guess one would have to be
> careful that there are no functions calling the functions you changed
> that _already_ adjust for FRAME_INTERNAL_BORDER_WIDTH, in which case
> they will double-adjust after the patch.  I did not find any, but I
> have not looked that carefully.

I did a grep in the source tree, and it seems these macros are not
used anywhere else in Emacs, except for one small reference in
Fwindow_vscroll:

FRAME_PIXEL_X_FROM_CANON_X:
        src/window.c:788: Fcoordinates_in_window_p
        src/window.c:943: Fwindow_at

FRAME_PIXEL_Y_FROM_CANON_Y:
        src/window.c:789: Fcoordinates_in_window_p
        src/window.c:944: Fwindow_at

FRAME_CANON_X_FROM_PIXEL_X:
        src/window.c:799: Fcoordinates_in_window_p

FRAME_CANON_Y_FROM_PIXEL_Y:
        src/window.c:800: Fcoordinates_in_window_p
        src/window.c:6167: Fwindow_vscroll

Unfortunately, `window-vscroll' doesn't like my patch:

        (set-frame-parameter nil 'internal-border-width 20)
        (set-window-vscroll nil 0.2) ==> -1.13, should be around 0.2
        (window-vscroll) ==> -1.13, should be around 0.2

> I guess an alternative would be to make the adjustment inside
> `window-at' and `coordinates-in-window-p'.

I think it's easier to adjust the pixel coordinates right inside
coordinates_in_window_p, which both functions use:

*** orig/src/window.c
--- mod/src/window.c
***************
*** 607,612 ****
--- 607,616 ----
    int grabbable_width = ux;
    int lmargin_width, rmargin_width, text_left, text_right;
  
+   /* Adjust for the frame's internal border. */
+   *x += FRAME_INTERNAL_BORDER_WIDTH (f);
+   *y += FRAME_INTERNAL_BORDER_WIDTH (f);
+ 
    if (*x < x0 || *x >= x1)
      return ON_NOTHING;
  

2004-07-24  Károly Lőrentey  <address@hidden>

        * window.c (coordinates_in_window): Adjust pixel coordinates to
        skip the frame's internal border.

Changeset: address@hidden/emacs--lorentey--0--patch-70

fix-coords-2.cset.tar.gz
Description: Binary data

This three-line patch fixes all problems with `window-at' and
`coordinates-in-window-p', and as far as I can see it does not affect
any other part of Emacs.

Yet another way to fix the problem would be to change the window-edges
family of functions to return ugly floats instead of nice round
integers, but on the Lisp level I think it's better to have the
frame's origin inside the frame's border.  I like the above patch the
most.

> A patch that Richard sent me and that does this for `window-at'
> strangely enough seems to fail by making `window-at' return nil
> everywhere:

This is strange, as the two patches look to be equivalent.

> *** window.c    20 Jul 2004 16:52:30 -0400      1.471
> --- window.c    23 Jul 2004 20:05:29 -0400
> ***************
> *** 937,944 ****
>     CHECK_NUMBER_OR_FLOAT (y);
>
>     return window_from_coordinates (f,
> !                                 FRAME_PIXEL_X_FROM_CANON_X (f, x),
> !                                 FRAME_PIXEL_Y_FROM_CANON_Y (f, y),
>                                   0, 0, 0, 0);
>   }
>
> --- 937,946 ----
>     CHECK_NUMBER_OR_FLOAT (y);
>
>     return window_from_coordinates (f,
> !                                 (FRAME_PIXEL_X_FROM_CANON_X (f, x)
> !                                  + FRAME_INTERNAL_BORDER_WIDTH (f)),
> !                                 (FRAME_PIXEL_Y_FROM_CANON_Y (f, y)
> !                                  + FRAME_INTERNAL_BORDER_WIDTH (f)),
>                                   0, 0, 0, 0);
>   }

-- 
Károly

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